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Scalable PSU/regulator GB

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#222
Yes, everything fits (my son would have been upset if he had to repack 150 kits). My previous boards were built with 1.5" heat sinks. The 2" gengis models look huge.

Like all Aavid sinks of this type, there are three mounting holes, and one of them is right in the middle of the die when a TO-220 is mounted. If you use an Aavid "maxclip07" and turn the sinks upside down the die lands on metal and the clip exerts more even force on the package than a screw through the tab. You can either pull the pins and reinsert them in the other end of the extrusion or simply use #4 sheet metal screws to attach the sinks to the boards.

I haven't tried a zener reference yet. I haven't even had a chance to connect the new regs up to my current crossovers. Enough play time though, I need to get this stuff out of my living room!
 
#223
For those outside the US -

Please send me your telephone number if you have not done so already. USPS wants it for online shipping.

If you just purchased boards without parts kits or additional caps I don't need your phone number.

US orders are packed and will ship today or tomorrow.
 
#224
Hi,
checking currents through the LTP (planning for 70Vdc input 60Vdc output).

The following apply to 15Vdc as most builders will be aiming for about this output voltage.

Ic of T3 = [VbeT1 +VbeT2] / R1 = [0.65+0.65]/1k0=1.3mA
IR10= [Vref-VbeT3]/R10=[10-.6]/1k0=9.4mA.

Are these answers correct?

If so, why is Ic of T4=8.1mA? when it should be equal to Ic of T3. A ratio of 6.2 mismatch.

Should R10 & R12 be 3k6? to reduce the LTP tail current to about 2.6mA?

Any comments anyone?
 
#227
Hi Peranders,
while the regulator is operating the T1 & T2 base emitter junctions generate a voltage drop of about 0.6V to 0.7V each.

This relatively constant voltage (about 1.3V total) appears across R1 (1k0).
Therefore the current in R1 is held reasonably constant at about 1.3mA

The current passing down to T3 is this same R1 current (I R3) plus the output current divided by the current gain of the darlington connected T1 & T2. At 200mA output the base current of T2 is about 0.05mA. therefore the T3 collector current (IcT3) ~=1.35mA and is held reasonably constant at this value. Small changes in this T3 current is the control on the darlington pair that provides the output voltage.

Is my explanation clear?
 
#232
I'm on my way to the post office with US shipments. You should have received an email with the tracking number.

The rest of the orders will go out over the next few days. I really want to have the weekend to build a few filter boards.
 
#238
There have been a couple of packing errors noted. Please email me directly if you have the wrong stuff in your package. I'll make it right.

I suspect some will find filter boards instead of PSU boards. I don't have as many filters and more PSUs than I thought I would. There are enough filter boards to cover those ordered, but I only have a few for myself. I'd sure appreciate getting them back.
 
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